I usually limit original mother boards and original BMDC SX machines to no higher than ver 3.02. As EMI said, there are a lot of variables but going higher/newer has a high probability of not working.
It is not the X axis that may be the problem but the Y axis. There were 2 versions of ball screws for the Y. One bolted to the nut block from the rear, the other from the front. They are not interchangeable. Look before ordering. Try Hardinge.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)